Archive for January, 2010
Tiny rotifers defeat the Red Queen
This week’s NPR Science Friday presented a fascinating report on rotifers, also known as “wheel animalcules”* due to the way they rotor food into their cylindrical bodies.** Besides being so funny-looking, these critters are unique in being only female — no guys to bother with (a bit of a bummer coming up as we are to Valentine’s Day). According to the Red Queen hypothesis this single gender situation should have put rotifers at an evolutionary disadvantage. However, these animalcules manage to thrive, albeit plagued by parasites. They survive by tolerating dehydration for amazing-long periods while riding the wind to their next home – typically a single drop of water.
Check out this entertaining Science Friday video on rotifers, which features new research by Paul Sherman and Chris Wilson of Cornell University. Warning: Although this production would be rated “G” for gender, it may not be suitable for children due to some horrifying imagery of lethal fungal parasites.
*Detailed in Welcome to the Wonderfully Weird World of Rotifers
**Seen in the brief video Life in a Drop of Water: Rotifer
Getting straight to the point via the word for today
Posted by mark in Basic stats & math on January 25, 2010
Today I learned a new aspect of geometry – the “symmedians” of a triangle. This esoteric term showed up in a review by Wall Street Journal writer Mark Laswell of a book on personal ads.* Here’s the appeal for a companion that caught my eye:
“Apparently the Three Symmedians aren’t a novelty Bosnian folk troupe. Rubbish mathematician (M 37).”
This diagram and detailing by Wolfram Mathworld tells you how to draw symmedians on a triangle and locate the symmedian point, which is the “isogonal conjugate” of the centroid.
It turns out that the centroid is a vital point for mixture design of experiments aimed at optimizing product formulations, as explained in this primer that I co-authored.
So that explains how the symmedian is an interesting ‘counter-point’ for me. However, I wonder if the self-styled “rubbish mathematician” attracted an isogonal conjugate with his play on geometry.
*(“Lonely Hearts, Like Minds The eccentric personal ads of ‘romantically awkward eggheads”)
Apples and oranges comparison of diets?
Posted by mark in science, Uncategorized, Wellness on January 21, 2010
While exercising on my elliptical machine this morning watching ABC’s Good Morning America the show captured my attention with a report that Weight Watchers (“WW”) this week filed a lawsuit against one of its top competitors, Jenny Craig (“JC”). The dispute stems from a claim by JC that their clients lost, on average, over twice as much weight as those on the largest weight loss program. WW alleges that this claim is deceptive due it comparing a study by JC done this year versus one done by WW 10 years ago. According to this news release by Weight Watchers the complaint states that generally accepted standards of biomedical research require Jenny Craig to compare the two current offerings of both companies through a head-to-head randomized clinical trial.
“You can’t compare studies that were done in different locations at different times using different groups of people.”
– Louis Aronne, M.D, New York Presbyterian Hospital weight loss expert and author of Eat This, Not That
Although the judge has put a temporary restraining order against their offending ad, I wouldn’t rule out the JC claim prima facie. After all, as Smartmoney Magazine writer Angie Marek stated in her column on The Skinny on Big, Fat Diet Programs “the science on most of these plans is hardly conclusive, since most of the research has been paid for by the diet companies themselves.” In fact, I predict that this case will keep at least two statisticians fat and sassy as expert witnesses (one on each side of this tug-of-war).
Marketing researchers go curb mining for treasure in the trash
Posted by mark in Uncategorized on January 16, 2010
The January Twin Cities Business magazine reported “A Real Good Marketing Experiment” that I found intriguing. Minneapolis-based Blu Dot Design and Manufacturing researchers abandoned 25 of their Real Good chairs on New York City sidewalks. See the results in this very entertaining eight-minute film.
“Once in a while you find some really good stuff.”
– A ‘Punko’ (scrounger) in the Real Good chair experiment.
In our suburban neighborhood we put out furniture and tape a sign on it that says “Free.” Whenever I’ve done this, the item has disappeared. A few times I’ve spied a person carting it off, but most stuff goes off with the garbage, I guess.
I suggest that the next time Blu Dot tosses out chairs they do a proper design of experiment (DOE). The measure of success will be how long it takes for a particular unit to be scrounged. The experimental factors will be color and various design elements. Of course the chairs must be laid out according to a randomized plan.
Stat-Ease performed a very simple, but statistically powerful, experiment on the chairs it considered for purchase in a new training room. See the details in this lead article of the June 2002 Stat-Teaser newsletter.
Management Blog Carnival, Review 3 – Seth Godin blog
Posted by mark in Uncategorized on January 3, 2010
(Note: This blog is the last of three in a carnival organized by John Hunter.
I picked the Seth Godin blog to review because his name rang a bell, but I’d never read anything by him that I specifically recall. As it turns out, I really did not see much that interested me greatly for exactly the opposite reason expressed in this comment by “ariana10” to Godin’s blog of 8/22 (bulleted below):
“I relate to this blog because I am a journalism major at the University of Kansas and I can’t do math for the life of me.”
I am an engineering major who likes math (in moderation!) and I can do it for the life of me. However, I am also keen on marketing and business (MBA, U Minn., ’80) so, even though Godin is light on stats, I must admit that he’s got much to offer for those of us trying to make a living in this high-tech world. Here are a few Seth Godin blogs of 2009 that hit my hot buttons.
- 1/24 Good guys finish… Godin suggests that under the bright light of the internet being generous and fair in business dealings pays off now more than ever. I like that idea a lot.
“When your customer service policies delight rather than enrage, word of mouth more than pays your costs.”
- 8/22 Not so good at math demonstrates the confusion creating by using miles per gallon (mpg) as the metric for fuel efficiency. As I noted in my blog on how the Inverse transformation puts mileage comparisons on track / the best measure for fuel efficiency is gallons per ten-thousand miles.
- 8/28 Spare no expense! does get somewhat quantitative (finally a graph!) in discussing the tradeoffs of giving almost no personal service to a huge number of users (Google) versus a great deal of attention to the troublesome individuals who soak it up.
- 10/26 Dunbar’s Number isn’t just a number, it’s the law is where Godin, a people person, draws the line at 150 – the limit predicted by British anthropologist Robin Dunbar for stable social relationships. I think the number might be a lot less (a tenth?) for engineers than marketers. ; )
What sets Seth Godin’s blog apart from the others I’ve seen (admittedly a small sample) is the amount of original content laced with thought-provoking observations of how people interact and what turns them on or off. He’s a guy worth keeping an eye on, I think.
Management Blog Carnival, Review 2 – “Hexawise” by Justin Hunter
Posted by hank in design of experiments, Uncategorized on January 1, 2010
(Editor’s note: This blog is contributed by my son Hank – a programmer by profession. It’s the second of three in a carnival organized by John Hunter. -Mark)
Justin Hunter is the founder of Hexawise, a SaaS tool that aids in setting up tests for software using statistical methods. This also happens to be the subject of his blog – no doubt influenced in part by his father, William Hunter, author of the classic text Statistics for Experimenters. Justin started the blog mid-way through ’09, so the pickings are a little slim, but there is still plenty of good stuff.
Some highlights from 2009:
- 10/6 The Stackoverflow.com for Software Testers marks the release of a beta version of testing.stackexchange.com. This is a community driven Q and A site that uses the same technology as Stack Overflow, a popular site for coders looking for help. Hunter’s version is aimed at testers, and already has an impressive database of answers and discussion.
- 8/25 What Else Can Software Development and Testing Learn from Manufacturing? Don’t Forget Design of Experiments (DoE) links to a Tony Baer post comparing software development to the manufacturing industry. Hunter further focuses on the application of Design of Experiments, pointing out the extensive use of DoE in quality improvement initiatives in Toyota and Six Sigma. These initiatives have yet to really penetrate the software development industry, despite some high profile successes (Google’s Website Optimizer and Youtube are mentioned).
- 12/9 Defect Seen >10 Million Times and Still not Corrected has some interesting trivia about the grammatical error in Lands’ End – something I hadn’t even noticed, and apparently the company hadn’t either until it was too late. The real point of the post, however, is to point out another much more fixable grammatical error in Google’s Blogger software. If there is only 1 comment on a post, it still says “1 comments”, instead of dropping the s. A trivial defect, perhaps, but a very visible and easily fixed one. It reminds me of something Mark always says about taking a break from work to sweep the dirt off the shop floor. That is, you shouldn’t let the little inconsequential bugs pile up while you’re focused on the big ones.
On a lighter note, in Famous Quotes that Make Just as Much Sense When You Substitute PowerPoint for Power Justin linked to a post by Jerry Brito about substituting PowerPoint for Power in famous quotes, adding a few of his own. I’d also like to add:
Kirk: “Spock, where the hell’s the PowerPoint you promised?”
Spock: “One damn minute, Admiral.” –Star Trek IV